For those of you without enough time and/or money for SIGGRAPH:
Pixar's Manuel Kraemer told the Siggrpah conference last week that the code is used at Pixar and that a full release is due late in 2012. Kraemer also said the studio has decided to freely licence some of its patents to make it possible to use Open SubDiv without attendant angst about future legal worries.
Open Subdiv relates to subdivision surfaces. One would assume that, coming from Pixar, there's probably some pretty neat stuff in there.
Mind you, the license will apparently be Ms-PL, which is, well, not totally open. (Essentially, Ms-PL forces derived work to adopt Ms-PL, and limits your licensing choices. Not the most egregious of things, but still...)
Actually, a collegue just informed me the Github repo is up as of three days ago:
How soon is now?
I wouldn't try to get near it for a while.
It was slashdot'ed